Study of the occupied electronic density of states of carbon samples by using second derivative carbon KVV Auger spectra

With the aim of extracting information on the electronic structure of carbon-based materials, double-differentiated C KVV Auger lines of graphite, diamond and different amorphous carbon (a-C) samples have been obtained using the XAES (X-ray excited Auger electron spectroscopy) technique. Comparison with theory and data taken from other experimental methods has shown that the structures found in the second-derivative Auger C KVV spectra can be satisfactorily explained, to first approximation, in the frame of a simplified Auger transitions model and that they reflect the behaviour of the occupied DOS (density of states) of the material under study. The second-derivative C KVV Auger analysis was shown to be very surface sensitive and able to deliver simultaneous information about p- and s-bonding character in the valence band electronic structure otherwise not obtainable with common photoemission techniques like UPS (ultraviolet photoelectron spectroscopy) and XPS (X-ray photoelectron spectroscopy).